摘要
为了研究小麦对强光的响应过程,以小偃54幼苗为试材,检测了强光处理0、1、3、8、24和48h的光合速率、叶绿素含量、最大光化学效率、抗氧化酶活性及色素结合蛋白基因的表达变化。结果表明,当小麦从低光转入强光后,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)变化呈单峰曲线,均在强光8h达到最大值,而在强光48h下降至强光处理前的水平;叶绿素b含量降低,叶绿素a/b升高;PSII最大光化学效率降低,热耗散增强;抗氧化酶如SOD、CAT、APX和GR活力诱导增强,均在强光处理48h达最大值。强光处理8h后LHCII亚基基因表达受到明显抑制,强光处理48h降至最低,早期光诱导蛋白基因在强光处理3h诱导表达,而在强光处理8h后表达量降低,叶黄素循环的关键酶VDE和ZEP基因的表达也在强光处理48h降至最低。
When plants absorb excessive light energy, a large number of reactive oxygen species is generally produced resulting in the degradation of DNA, proteins, and pigments in plants. For wheat （Triticum aestivum L.） grown in North China, the photooxidation induced by high light （HL） during grain-filling period usually causes great losses in grain yield. It is important to understand the mechanism of wheat plant in response to HL for HL-tolerant breeding in wheat. Xiaoyan 54, a wheat cultivar with high resistance to HL, is an ideal material to disclose photosynthesis characteristics of wheat when exposed to HL. In this study, the third-leaf seedlings of Xiaoyan 54 were grown under the condition low light to HL in a growth chamber. The seedlings were sampled at 0, 1, 3, 8, 24, and 48 h after HL treatment. Simultaneously, the net photosynthetic rate （Pn）, chlorophyll content （Chl）, and fluorescence parameters were measured with the second leaf. The activities of antioxidant enzymes, such as superox-ide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX）, and glutathione reductase （GR）, were also determined. In addition, expression pattern of the pigment binding protein related genes were evaluated. The results showed that Pn increased in the photosynthetic induction stage that was from 0 h to 8 h of HL treatment, but decreased continuously during the photoinhibi-tion stage that was from 8 h to 48 h of HL treatment. The maximum Pn value of 18 μmol CO2 m？2 s？1 was observed at the 8 h timepoint of HL treatment. The parameters Gs, Ci, and Tr changed similarly to Pn and reached the peaks at the 8 h timepoint of treatment. The contents of total chlorophyll and chlorophyll a only changed slightly during the 48 h of HL treatment. In contrast, chlorophyll b reduced significantly from 24 h to 48 h of treatment, and the ratio of chlorophyll a/b increased from 8 h to 48 h of HL treatment. At the one hour timepoint of HL treatment, the maximum quantum efficiency of PSII （Fv/Fm）, the ma
出处
《作物学报》
CAS
CSCD
北大核心
2010年第3期449-456,共8页
Acta Agronomica Sinica
基金
国家自然科学基金项目(30330390)
国家重点基础研究计划(973计划)项目(2002CB111304
2009CB118506)
中国科学院知识创新工程(KSCX1-YW-03
KSCX2-YW-N-046)
引进国际先进农业科学技术计划(948计划)项目(2006G2)资助
关键词
小麦
强光
光氧化
基因表达
Wheat
High light
Photooxidation
Gene expression
